Loans and Leases (Details 7) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 134,275		$ 139,456
Charge-offs	(18,235)		(30,388)
Recoveries	1,099		8,297
Allowance for Loan and Lease Losses, Net charge-offs	(17,136)	$ (24,348)	(22,091)	$ (44,767)
Provision	15,000		14,774
Balance, end of period	132,139		132,139
Amount of the allowance applicable to loans and leases:
impairment	8,952		8,952
impairment	123,187		123,187
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	167,157		167,157
impairment	16,718,035		16,718,035
Ending balance of loans and leases	16,885,192		16,885,192		$ 16,972,743
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		149,826	133,012	143,755
Charge-offs		(22,951)		(43,879)
Recoveries		2,004		4,743
Allowance for Loan and Lease Losses, Net charge-offs		(20,947)		(39,136)
Provision		10,000		34,260
Balance, end of period	138,879	138,879	138,879	138,879
Amount of the allowance applicable to loans and leases:
impairment		13,312		13,312
impairment		125,567		125,567
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		227,774		227,774
impairment		15,243,257		15,243,257
Ending balance of loans and leases		15,471,031		15,471,031	16,914,707	[1],[2],[3]
Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period			6,444
Balance, beginning of period		11,481		13,483
Charge-offs		(3,459)		(5,689)
Recoveries		58		58
Allowance for Loan and Lease Losses, Net charge-offs		(3,401)		(5,631)
Provision		(1,001)		(773)
Balance, end of period	7,079	7,079	7,079	7,079
Amount of the allowance applicable to loans and leases:
deteriorated credit quality		7,079		7,079
The ending balance of the loan and lease portfolio is composed of loans and leases:
deteriorated credit quality		72,426		72,426
Ending balance of loans and leases		72,426		72,426	58,036
NonPCI and PCI Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		161,307		157,238
Charge-offs		(26,410)		(49,568)
Recoveries		2,062		4,801
Provision		8,999		33,487
Balance, end of period	145,958	145,958	145,958	145,958
The ending balance of the loan and lease portfolio is composed of loans and leases:
Total loans and leases		15,543,457		15,543,457
Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs		(3,401)		(5,631)
Real Estate Mortgage
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	40,158		40,051
Charge-offs	(4,747)		(7,345)
Recoveries	120		1,777
Allowance for Loan and Lease Losses, Net charge-offs	(4,627)	(122)	(5,568)	(1,436)
Provision	9,936		10,984
Balance, end of period	45,467		45,467
Amount of the allowance applicable to loans and leases:
impairment	472		472
impairment	44,995		44,995
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	83,931		83,931
impairment	7,482,443		7,482,443
Ending balance of loans and leases	7,566,374		7,566,374
Real Estate Mortgage | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		35,368		37,765
Charge-offs		(142)		(1,686)
Recoveries		20		250
Provision		1,876		793
Balance, end of period	37,122	37,122	37,122	37,122
Amount of the allowance applicable to loans and leases:
impairment		1,415		1,415
impairment		35,707		35,707
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		117,441		117,441
impairment		5,954,357		5,954,357
Ending balance of loans and leases		6,071,798		6,071,798	7,798,991	[1],[2]
Real Estate Construction and Land
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	18,190		13,055
Charge-offs	0		0
Recoveries	17		26
Allowance for Loan and Lease Losses, Net charge-offs	17	9	26	17
Provision	8,003		13,129
Balance, end of period	26,210		26,210
Amount of the allowance applicable to loans and leases:
impairment	0		0
impairment	26,210		26,210
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	15,998		15,998
impairment	1,858,028		1,858,028
Ending balance of loans and leases	1,874,026		1,874,026
Real Estate Construction and Land | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		10,476		10,045
Charge-offs		0		0
Recoveries		9		17
Provision		833		1,256
Balance, end of period	11,318	11,318	11,318	11,318
Amount of the allowance applicable to loans and leases:
impairment		0		0
impairment		11,318		11,318
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		5,840		5,840
impairment		1,157,500		1,157,500
Ending balance of loans and leases		1,163,340		1,163,340	1,591,229	[1],[2]
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	73,780		84,022
Charge-offs	(13,425)		(22,949)
Recoveries	912		6,399
Allowance for Loan and Lease Losses, Net charge-offs	(12,513)	(20,743)	(16,550)	(37,580)
Provision	(2,461)		(8,666)
Balance, end of period	58,806		58,806
Amount of the allowance applicable to loans and leases:
impairment	8,480		8,480
impairment	50,326		50,326
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	67,228		67,228
impairment	6,998,884		6,998,884
Ending balance of loans and leases	7,066,112		7,066,112
Commercial | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		102,134		93,853
Charge-offs		(22,696)		(41,981)
Recoveries		1,953		4,401
Provision		6,973		32,091
Balance, end of period	88,364	88,364	88,364	88,364
Amount of the allowance applicable to loans and leases:
impairment		11,564		11,564
impairment		76,800		76,800
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		104,008		104,008
impairment		7,733,659		7,733,659
Ending balance of loans and leases		7,837,667		7,837,667	7,114,920	[1],[2]
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	2,147		2,328
Charge-offs	(63)		(94)
Recoveries	50		95
Allowance for Loan and Lease Losses, Net charge-offs	(13)	(91)	1	(137)
Provision	(478)		(673)
Balance, end of period	1,656		1,656
Amount of the allowance applicable to loans and leases:
impairment	0		0
impairment	1,656		1,656
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment	0		0
impairment	378,680		378,680
Ending balance of loans and leases	378,680		378,680
Consumer | Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period		1,848		2,092
Charge-offs		(113)		(212)
Recoveries		22		75
Provision		318		120
Balance, end of period	$ 2,075	2,075	$ 2,075	2,075
Amount of the allowance applicable to loans and leases:
impairment		333		333
impairment		1,742		1,742
The ending balance of the loan and lease portfolio is composed of loans and leases:
impairment		485		485
impairment		397,741		397,741
Ending balance of loans and leases		398,226		398,226	$ 409,567	[1],[2]
Non Purchased Credit Impaired Loans and Leases
Allowance for Loan and Lease Losses [Roll Forward]
Allowance for Loan and Lease Losses, Net charge-offs		$ (20,947)		$ (39,136)

[1] Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

[2] Excludes loans held for sale carried at lower of cost or fair value and PCI loans.

[3] Excludes loans held for sale carried at lower of cost or fair value and PCI loans.